Senate Republicans have passed their tax bill, and the President has dubbed it an historic moment. Here are words I never imagined I’d say: He’s right. Because this is a historically bad bill: not just the most unpopular tax legislation in forty years, not just the most brazen federal boon to billionaires in modern memory, but the first ever so-called tax bill to strip 13 million Americans of their health insurance.

Currently, the GOP’s stealth attack on Obamacare appears only in the Senate bill, not in the one passed by the House. In coming weeks, the House and the Senate will combine their bills into a version they both agree on. If Republicans in Congress manage to jam repeal into this final bill, history won’t just be made, it will be repeated. The President and his party will throw the country back into a time when too many Americans could not access the medical treatment that would save their lives.

We’ve been framing the tax debate as a question of economics: Should we strip the middle-class of crucial deductions to put more money in the hands of corporate investors? Should we sacrifice the future of Medicare and other essential social service programs to save the President’s family business a few (million) bucks? Should we blow up the federal deficit and trigger catastrophic spending cuts? (The GOP’s response: yes, absolutely, and sure, why not?)

Here’s the question we should be asking: If this bill passes, will it be harder for me to protect my health and the health of the people I love?

The answer: another resounding yes. The Republicans in congress have smuggled a time bomb into their bill, and when it goes off, it will explode our individual health insurance system.

Back in July, the Senate voted down a “skinny repeal” of the Affordable Care Act. The centerpiece of that effort was the elimination of the “individual mandate,” a requirement that anyone who can afford to purchase insurance does so. This may sound like a minor change. It would in fact be catastrophic.

As a policy advisor in Obama’s Department of Health and Human Services, I helped roll out many of the reforms within the ACA. In the process, I came to understand that a stable market depends on both the sick and the healthy buying insurance , which means without the mandate, the whole system falls apart. There’s good reason the American Medical Association, the AARP, the American Cancer Society Action Network, and a bipartisan group of governors all rallied against skinny repeal. They believed it would put millions of Americans at risk.

They were right.

Senate Republicans have tried again and again to repeal Obamacare. Again, and again, they’ve failed. They failed because we, the people they represent, want affordable access to health care, and we made our voices heard. Now congressional Republicans have resurrected skinny repeal from the dead and slapped a new name on it. Under the guise of a tax bill, they’re trying yet again to abolish the individual mandate, hoping this time, no one will notice.

They think they can get away with this because the mandate itself isn’t popular. No one likes being told what to do, much less what to buy. But when healthy people aren’t required to buy insurance, fewer of them do. This leaves behind a higher percentage of sick people in the insurance market , which raises costs for the insurance companies. So, insurers shift these costs to consumers, and everyone’s rates rise. When they do, this drives even more people out of the market, and the market edges closer to collapse. Here comes the GOP’s favorite part: The fewer people who can afford to buy even subsidized insurance, the less money the government must pay out.

The nonpartisan Congressional Budget Office estimates that one year after repeal, 4 million fewer people would have health insurance. By 2027, that number rises to 13 million. Those remaining on the individual market will pay 10% higher rates every year — and that’s in the lucky state markets that survive. Meanwhile, the government nets $338 billion to pay for its corporate tax cuts. Or, I should say, to pay for a fraction of its corporate tax cuts, keeping their cost to a mere $1.5 trillion.

To be clear: The GOP isn’t denying this. They’re counting on it. If 13 million people don’t lose access to health care, congressional Republicans don’t get their $338 billion.

You don’t have to be on the individual insurance market to bear the burden of its destruction. When uninsured people get sick, they’re legally entitled to emergency care — and someone must pay for it. A portion of that cost falls on hospitals, which could be forced to close their doors. A portion of the cost falls on insurers, who could compensate by raising your rates. And the remaining billions of that cost will fall directly on the American taxpayer — you.

Then, of course, there’s the human cost. As a registered nurse, I know all too well what happens when a cancer patient can’t afford chemotherapy, when a cardiac patient can’t afford a new defibrillator battery, when a diabetic patient can’t afford insulin. For many Americans, this tax bill could be a death sentence — and that’s a higher cost than any of us should be willing to pay.

The Republicans in congress can call it whatever they’d like, but this is not tax reform. This is health care repeal. This is a stealthy slashing of the social safety net. And this is all for the sake of income redistribution — shifting ever more money from the poor and middle-class to the rich. It’s fiscally irresponsible and morally bankrupt.

Affordable health care can still be saved — but only if enough House Republicans stand up to their party, their President, and their wealthy donors. Unfortunately, congressional Republicans don’t seem to mind that their constituents hate this bill, as long as those donors love it.

The billionaires who fund the Republican Party have made themselves clear: give us our tax break, or the donations dry up. By supporting this bill, our representatives have in turn sent us a very straightforward message: We don’t care about you, unless you’re in the top 1%. We don’t care that the ballooning deficit could trigger billions in automatic cuts to programs like Medicare, the Student Loan Administration, and the Military Retirement Fund. We don’t care that your taxes might actually go up, or that your state and local budgets might be gutted. And we certainly don’t care about your health.

A vote for this bill says: We only care about the wealthy donors who fund our campaigns. We only represent them.

Anyone willing to say that should lose their privilege to represent us.

Lauren Underwood is a registered nurse, health policy expert and former Senior Policy Advisor in the US Department of Health and Human Services. She’s running for Congress in Illinois’s 14th Congressional District against Tea Party Republican, Randy Hultgren, who voted to support the House Tax Plan.